| Abstract: | Extension springs that can be manufactured to a small size with a precise
free length are described herein. An extension spring comprises a first
drawbar member and a second drawbar member that extend along a same
direction. The extension spring further comprises a compression spring
coil that surrounds respective portions of the draw bar members. At
either end of the spring coil are positioned end caps that surround the
drawbar members. The end caps provide flat surfaces on which the ends of
the spring coil rest in a resting position of the extension spring. The
end caps are held against bent ends of arms of the drawbar members by
tension of the spring coil. When the drawbar members are drawn apart from
one another, the end caps compress the spring coil. Compression of the
spring coil causes forces that resist the motion of the drawbar members
apart from one another. |